This invention relates to hospital beds and more particularly to hospital beds having wheels or casters attached to a base frame for rolling the bed from location to location and a braking and steering mechanism for controlling the casters.
Hospital beds are typically designed to be moved from location to location in a hospital or other health care facility. Therefore, beds have wheels or casters which permit the hospital bed to be rolled and steered between locations. During movement it is desirable to have free rolling wheels but upon reaching the desired location, brakes are usually applied to the wheels to maintain the bed at the desired location.
It is well known to provide hospital beds with brake/steer casters which include mechanisms for blocking the rotation of the casters, i.e. braking mechanisms, and mechanisms for blocking swiveling movement of the caster fork, i.e. anti-swivel or directional lock steering mechanisms. Some beds with four castered wheels include pedals located on opposite sides of the bed which control the braking and anti-swivel mechanisms in each caster. Examples of such beds are shown in U.S. Pat. No. 5,377,372 and PCT Publication No. WO 00/51830 both of which are incorporated herein by reference.
According to one embodiment of the present invention, a caster apparatus comprises a wheel having an axis of rotation, and a brake system including a brake member coupled to the wheel for rotation about the axis of rotation of the wheel and a cable having a first end portion coupled to the brake member and a second end portion. The apparatus also comprises an actuator coupled to the second end portion of the cable. The actuator is actuatable to move the cable, thereby rotating the brake member about the axis of rotation to brake the wheel.
In one illustrated embodiment, the apparatus further comprises a sleeve. The wheel is rotatably coupled to the sleeve and defines a first sweep pattern as the wheel rotates relative to the sleeve. The brake member defines a second sweep pattern as the wheel rotates relative to the sleeve. The first sweep pattern is illustratively greater than or equal to the second sweep pattern.
According to another embodiment of the present invention, a caster apparatus comprises a wheel including a first side wall, a second side wall, and an outer edge extending between the first and second side walls. The outer edge defines a circumference of the wheel, and the wheel is rotatable about an axis of rotation. The apparatus also comprises an external brake member coupled to the wheel adjacent the first side wall and within the circumference of the wheel, and an actuator coupled to the brake member. The actuator is actuatable to cause the brake member to prevent rotation of the wheel about the axis of rotation.
According to yet another embodiment of the present invention, a patient support apparatus comprises a patient support surface, a frame coupled to the patient support surface, and caster apparatus coupled to the frame. The caster apparatus includes a wheel and a brake system including an actuator, a cable, and a brake member. The cable has a first end portion coupled to the actuator and a second end portion coupled to the brake member. Actuation of the cable by the actuator causing the brake member to rotate about an axis to brake the wheel.
According to a further embodiment of the present invention, a caster apparatus comprises a wheel including a first side wall, a second side wall, and an outer edge extending between the first and second side walls. The outer edge defines a circumference of the wheel. The wheel is rotatable about an axis of rotation. The apparatus also comprises a brake member coupled to the wheel. The brake member includes a plunger movable to brake the wheel. The plunger includes a brake surface located below the outer edge of the wheel. The apparatus further includes an actuator coupled to the brake member. The actuator is actuatable to brake the wheel using vertical movement of the plunger and brake surface as the sole braking force on the wheel.
In one illustrated embodiment, the brake surface is a friction brake which engages an inner surface of the wheel located within the circumference of the wheel to brake the wheel. In another illustrated embodiment, the brake surface is a friction brake which engages a floor when actuated by the actuator. In yet another illustrated embodiment, the wheel includes an inner surface having a plurality of teeth, and the brake surface of the plunger also includes a plurality of teeth which mate with the plurality of teeth on the inner surface of the wheel to brake the wheel.
Additional features and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of illustrated embodiments exemplifying the best mode of carrying out the invention as presently perceived.